Textile interlacing jets have been found to be a source of a substantial amount of noise. They can result in an undesirable work environment if a number of jets are provided in the same work area. Practical problems in muffling such noise have been great due to the fact that the interlacing jet operates at fluid velocities of about 0.3-0.6 times the speed of sound, and the noise is typically very high frequency (on the order of 3 kHz to 20 kHz). The mufflers must be able to achieve substantial noise reduction (e.g., on the order of about 15 to 20 dB(A)) while not adversely affecting the yarn being processed.
Typical prior art suggestions for mufflers for interlacing jets utilize dissipative mufflers, which include sound absorbing material that converts incident sound into heat. Typical of such a muffling apparatus is that disclosed in U.S. Pat. No. 3,713,509. While dissipative mufflers can perform their sound-reducing function, the sound absorbing material associated therewith can become contaminated with size and lint, thereby significantly reducing its performance and requiring a substantial amount of maintenance. Additionally, proposed dissipative muffler designs require relatively bulky structures, which can interfere with normal operator procedures.
According to the present invention a muffler for an interlacing jet is provided that requires very little maintenance, does not substantially increase the size of the interlacing jet, and yet functions so as to produce substantial noise reductions, on the order of 15 to 20 dB(A). This is accomplished according to the present invention by utilizing reactive muffler means in association with both the yarn inlet and yarn outlet of the jet, each reactive muffler means including a large expansion chamber and a restricted inlet or outlet. The change in cross-sectional area from the expansion chamber to the restricted inlet or outlet is abrupt; i.e., the ratio of the areas is at least about 9 to 1, and preferably at least about 25 to 1. The invention is effective despite the fact that the fluid velocity and noise frequency ranges associated with an interlacing jet are substantially different from these ranges in environments where reactive mufflers are conventionally employed. Most conventional applications of reactive mufflers are restricted to fluid velocities of less than about 0.2 times the speed of sound, and typically in the 50 Hz to 1 kHz frequency range.
By utilizing the muffled textile interlacing jet according to the present invention, a method of muffling sound from the jet is provided, the jet operating with fluid velocities of about 0.3-0.6 times the speed of sound and producing noise in the frequency range of about 3 kHz to 20 kHz. A first reactive muffler is placed in operative association with the jet yarn inlet, and a second reactive muffler is placed in operative association with the jet yarn outlet. The mufflers are effective to achieve a reduction in sound in the 3 kHz to 20 kHz range of about 15 to 20 dB(A), or sometimes even more. The mufflers are maintained in place as the yarn passes therethrough, and through the interlacing jet for interlacing, the mufflers not adversely affecting the properties of the yarn.
It is the primary object of the present invention to provide for the reactive muffling of a textile interlacing jet. This andother objects of the present invention will become clear from an inspection of the detailed description of the invention, and from the appended claims.